JPH028162Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention includes a rotating shaft that is rotated against a return spring in conjunction with the angular displacement of the detected object, and an axis that is connected to the rotating shaft and that is connected to the rotating shaft. The present invention relates to an angular displacement amount detection device that includes a brush that is angularly displaced around the circumference and a resistor that the brush is in sliding contact with.

Conventionally, in this type of device, as will be described in detail later, an error occurs in the contact position of the brush with the resistor when the brush is displaced in a regular angle and when it is displaced in a reverse angle, and a so-called hysteresis phenomenon occurs in the detection output. This comes with certain inconveniences.

Therefore, the purpose of the present invention is to provide a device that can reduce such errors as much as possible, suppress the occurrence of hysteresis, and accurately detect the amount of angular displacement. The illustrated embodiment will be explained below.

FIG. 1 shows an embodiment in which the throttle valve 2 provided in the carburetor 1 of an internal combustion engine is used as the object to be detected, and its opening degree, that is, the angular position is detected by the present detection device. A flange portion 3a on the outer periphery of the front end of the casing 3 is fitted into a fitting portion 1a on the side of the container body of the carburetor 1, and the flange portion 3
A wave washer 4 as shown in Fig. 2 is attached to the back of a.
Furthermore, a holding plate 5 as shown in FIG. 3 is attached to the back side of the carburetor 1, and the bolts 6 are tightened and fixed to the carburetor 1, and the shaft 2a of the throttle valve 2 is attached to the fitting. Extends to the joining part 1a side and has approximately L at the end thereof.
A letter-shaped lever 2b is fixedly installed, and the lever 2b is engaged with the pivot shaft 7 supported by the casing 3 at the abutment pin 8 at the front end thereof, and the corresponding abutment pin 8 is engaged with the lever 2b.
a return spring 9 having one end engaged with the casing 3;
engage the other end. Due to the angular displacement of the throttle valve 2 toward the opening side, the rotating shaft 7 pushed by the lever 2b is rotated against the return spring 9.

To explain this in more detail, the rotating shaft 7 includes a large diameter part 7a and a small diameter part 7b, as clearly shown in FIG. Pivotally supported. The return spring 9 is formed into a coil shape and is inserted into a portion of the bearing 10 that protrudes from the end surface of the casing 3, and is connected to a corresponding contact pin 8 that is attached to the end surface of the casing 3 and the large diameter portion 7a. 5, one end of the spring 9 is connected to a protrusion 11 projecting from the end surface of the casing 3, and the other end is connected to the corresponding connecting pin 8, respectively. When engaged, the rotating shaft 7 is biased in the opposite direction (clockwise in FIG. 5) to the direction of angular displacement of the throttle valve 2.

Further, the casing 3 includes a cylindrical portion 3b at the rear end, and accommodates therein a disc-shaped brush holder 12 fixed to the rear end of the rotating shaft 7 and a resistance board 13 facing the brush holder 12. A pair of radially outer and inner brushes 15, 1 are attached to the holder 12 through a metal support piece 14 on the back surface of the holder 12, as shown in FIG.
6 is attached to the base plate 13 so that the brushes 15 and 16 are angularly displaced around the axis of the rotation shaft 7 as the rotation shaft 7 rotates.
A pair of resistors 17 and 18 with which the resistors 6 are in sliding contact are attached so that the amount of angular displacement can be detected as a change in the low resistance value.

Referring to FIG. 7, an input terminal 19 and a ground terminal 20 are connected to both ends of the first resistor 17, which is in sliding contact with the first outer brush 15, and a second resistor 17, which is in sliding contact with the second outer brush 16, is connected to an input terminal 19 and a ground terminal 20, respectively. An output terminal 21 is connected to the main part of the resistor 18, and a detection output corresponding to the resistance value of the first resistor 17 between the input terminal 19 and the contact position of the first brush 15 is transmitted to the second brush 16. It was arranged to be taken out to the output terminal 21 via the second resistor 18.

Note that the second resistor 18 functions as a conductor for taking out the detection output, and in this case, if the output is taken out directly from the support piece 14 via a lead wire, the second brush 16 and the The second resistor 18 becomes unnecessary.

In the drawing, 22 connects the brush holder 12 to the wiring board 13.
A wave washer 23 is inserted between the holder 12 and the intermediate receiving surface 3c of the casing 3 facing the holder 12, and has approximately the same shape as that shown in the second figure. A stopper portion 24 protruding from the inner surface of the portion 3b is a stopper portion 24 for each of the terminals 19, 20,
The lead wire connected to 21, 25 is the lead wire 24
A grommet is shown for airtightly leading out the casing 3 to the outside of the casing 3.

The overall configuration of the angular displacement detection device has been described above. According to the present invention, the position of the point of action of the force of the return spring 9 on the rotation shaft 7 and the mounting position of the brushes 15 and 16 are as shown in FIG. They are arranged to lie on substantially the same diameter line a of the rotating shaft 7.

To explain this point in detail below, there is a slight clearance between the small diameter portion 7b of the rotating shaft 7 and the bearing 10 in order to rotatably support the rotating shaft 7. This causes the rotation shaft 7 to tilt, and when the rotation shaft 7 is pushed by the lever 2b and rotated in the normal direction due to the regular angular displacement of the throttle valve 2 toward the opening side, and when it is rotated in the normal direction by the return spring 9. When it comes to
An error occurs in the contact position of the brush 15 with the resistor 17, which causes hysteresis in the detection output.

To explain this in more detail, when the throttle valve 2 shifts from the opening operation to the closing operation, the rotation shaft 7 is rotated by the spring force F ₁ acting on the point of action on the cross pin 8 that engages the return spring 9. 5, the rotation is reversed clockwise. In this case, on the front end side of the rotating shaft 7, there is a torque T equal to the product of F1 and l, where the distance from the axis of the point of action is l, and a torque T that is equal to the product of _F1 and l, and A force F ₂ having the same magnitude and direction as F ₁ acts on the point of action, and this force F ₂ tilts the rotation shaft 7, so that the rotation shaft 7 is tilted toward the rear end as shown in FIG. 6. The rotation shaft 7 and the bearing 10
A force F ₃ perpendicular to the aforementioned diameter line a in the direction opposite to F ₂ acts with the point of contact with the brush 1 as a fulcrum, and
When the brushes 5 and 16 are located away from the diameter line a, for example, at the position indicated by A in FIG. 6, the brushes 15 and 16
Although this F ₃ force acts on the circumferential direction, since the deviation is not restricted in the circumferential direction, an error occurs between the positive angular displacement and the reverse angular displacement.

On the other hand, when the brushes 15 and 16 exist on the diameter line a as in the present case, the brushes 15 and 16
is pushed in the circumferential direction by a force of _F3 , and the above-mentioned error is reduced as much as possible, and the hysteresis of the detection output is also suppressed accordingly.

As described above, according to the present invention, the position of the point of action of the force of the return spring on the rotating shaft and the portion of the brush that slides into contact with the resistor are located approximately on the diameter line of the rotating shaft, and the position is correct. This has the effect that the error in the contact position of the brush with respect to the resistor during angular displacement and reverse angular displacement is reduced as much as possible, making it possible to accurately detect the amount of angular displacement with less hysteresis.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view illustrating the assembly of the proposed device and the object to be detected, Figs. 2 and 3 are perspective views of the wave washer and a front view of the holding plate used for the assembly, and Fig. 4 is a front view of the holding plate. FIG. 5 is a front view of the main part of one example of the device of the present invention, and FIGS. 6 and 7 are cross-sectional views taken along the line - and - of FIG. 4. 2... Detected object (throttle valve), 7... Rotating shaft, 9... Return spring, 15, 16... Brush, 1
7, 18...Resistor, a...Diameter wire.

Claims (1)

[Scope of utility model registration request] A rotating shaft that is rotated against a return spring in conjunction with the angular displacement of the detected object, a brush that is connected to the rotating shaft and angularly displaced about the axis of the rotating shaft, and the brush. In an angular displacement detection device comprising a resistor in sliding contact with the rotation shaft, the position of the point of application of the force of the return spring on the rotation shaft and the portion of the brush in sliding contact with the resistance body are located on the rotation shaft. An angular displacement detection device characterized in that the angular displacement amount is located approximately on a diameter line.